Roll paper supply device and printing device having the same

Abstract

A roll paper supply device has a roll paper compartment that stores roll paper with the axis of rotation transverse so that the roll paper can roll thereinside; supply rollers that feed the roll paper from the roll paper compartment in a sheet; and pair of side pressure plates that cover substantially all of the sides of the roll paper and contact part of the sides.

What is claimed is: 
     
       1. A roll paper supply device, comprising:
 a roll paper compartment that stores therein roll paper with a transverse axis of rotation so that the roll paper is rotatable inside the roll paper compartment, the roll paper compartment comprising:
 a roll paper holder having a first side plate that covers substantially an entirety of one side of the roll paper, the first side plate having a surface that contacts a part of the one side of the roll paper, and a bottom plate on which the roll paper is placed, and 
 a second side plate attached to a frame; 
 
 an urging member that urges the roll paper holder, including the bottom plate, toward the second side plate; and 
 supply rollers configured to feed a sheet pulled off the roll paper along a transportation path and downstream in a feeding direction; 
 wherein the surface of the first side plate that contacts the one side of the roll paper is inclined such that the first and second side plates converge toward each other so that a gap formed between the first and second side plates on a downstream side is narrower than a gap formed between the first and second side plates on an upstream side with respect to both a horizontal component and vertical component of the feeding direction in which the sheet is pulled off the roll paper by the supply rollers. 
 
     
     
       2. The roll paper supply device described in  claim 1 , further comprising:
 main feed rollers that are disposed downstream from the supply rollers and configured to hold and convey the sheet from the roll paper; 
 a tension mechanism that is disposed to the transportation path between the supply rollers and the main feed rollers, and is supported to maintain constant roll paper tension on the main feed rollers; and 
 sub-feed rollers that are disposed downstream from the main feed rollers and configured to hold and convey the sheet from the roll paper. 
 
     
     
       3. The roll paper supply device described in  claim 1 , wherein:
 the roll paper is arranged to be pulled upward from the bottom plate by a force of the supply rollers; and 
 the first side plate and second side plate are configured to contact the sides of the pulled up roll paper where the gap between the first side plate and second side plate across a width of the roll paper is narrow, and to hold the roll paper therebetween. 
 
     
     
       4. The roll paper supply device described in  claim 1 , wherein the first side plate directly contacts an uppermost part of the one side of the roll paper. 
     
     
       5. The roll paper supply device described in  claim 4 , wherein the first side plate is free of direct contact with a lower part of the one side of the roll paper, the lower part below a central axis of the roll paper. 
     
     
       6. The roll paper supply device described in  claim 5 , wherein the first side plate has a uniform thickness along the inclined surface. 
     
     
       7. The roll paper supply device described in  claim 1 , wherein the first side plate is free of direct contact with a lower part of the one side of the roll paper, the lower part below a central axis of the roll paper. 
     
     
       8. The roll paper supply device described in  claim 7 , wherein the first side plate has a uniform thickness along the inclined surface. 
     
     
       9. The roll paper supply device described in  claim 1 , wherein the first side plate has a uniform thickness along the inclined surface. 
     
     
       10. The roll paper supply device described in  claim 1 , wherein the urging member includes a spring that urges the roll paper holder toward the second side plate. 
     
     
       11. A printing device, comprising:
 a roll paper compartment that stores therein roll paper with a transverse axis of rotation so that the roll paper is rotatable inside the roll paper compartment, the roll paper compartment comprising:
 a roll paper holder having a first side plate that covers substantially an entirety of one side of the roll paper, the first side plate having a surface that contacts a part of the one side of the roll paper, and a bottom plate on which the roll paper is placed, and 
 a second side plate attached to a frame; 
 
 an urging member that urges the roll paper holder, including the bottom plate, toward the second side plate; 
 supply rollers configured to feed a sheet pulled off the roll paper along a transportation path and downstream in a feeding direction; and 
 a print head configured to print on the sheet supplied from the roll paper, 
 wherein the surface of the first side plate that contacts the one side of the roll paper is inclined such that the first and second side plates converge toward each other so that a gap formed between the first and second side plates on a downstream side is narrower than a gap formed between the first and second side plates on an upstream side with respect to both a horizontal component and vertical component of the feeding direction in which the sheet is pulled off the roll paper by the supply rollers. 
 
     
     
       12. A roll paper supply device, comprising:
 a roll paper compartment that stores therein roll paper with a transverse axis of rotation so that the roll paper is rotatable inside the roll paper compartment, the roll paper compartment comprising:
 a roll paper holder having a first side plate that covers substantially an entirety of one side of the roll paper, the first side plate having a surface that contacts a part of the one side of the roll paper, and a bottom plate on which the roll paper is placed, and 
 a second side plate attached to a frame; 
 
 an urging member that urges the roll paper holder toward the second side plate; and 
 supply rollers configured to feed a sheet pulled off the roll paper along a transportation path and downstream in a feeding direction; 
 wherein the surface of the first side plate that contacts the one side of the roll paper is inclined such that the first and second side plates converge toward each other so that a gap formed between the first and second side plates on a downstream side is narrower than a gap formed between the first and second side plates on an upstream side with respect to both a horizontal component and vertical component of the feeding direction in which the sheet is pulled off the roll paper by the supply rollers; 
 the roll paper supply device further comprising: 
 a roll paper cover rotatable between a closed position where the roll paper cover closes the roll paper compartment, and an opened position where the roll paper cover opens the roll paper compartment; and 
 a side plate release mechanism configured to move the first and second side plates away from each other in response to a rotation of the roll paper cover from the closed position to the opened position. 
 
     
     
       13. The roll paper supply device described in  claim 12 , wherein the side plate release mechanism includes a cam. 
     
     
       14. The roll paper supply device described in  claim 13 , wherein the cam has a width varying along a rotational direction of the roll paper cover. 
     
     
       15. The roll paper supply device described in  claim 14 , wherein the cam is curved along the rotational direction of the roll paper cover.